Officials in southern China have swooped on a brick factory and laid bare a vision from hell where labourers were forced to work 16 hours a day for the equivalent of less than 17p a month.

The discovery of the kiln was accompanied by revelations about a “black job agency” that traded the men as slaves and priced their lives at 400 yuan (£40) each.

What was happening in Huizhou, in the southern province of Guangdong, shines more light on the darkest side of China’s construction boom, a pace of building that has helped to propel the economy to the